Phakic intraocular lens (pIOL) is a promising alternative for correcting refractive error, especially for patients with moderate-to-high ametropia whose corneas are not suitable or contraindicated for corneal refractive procedures (1). This category of refractive surgery has been rapidly growing both in the United States and worldwide. The Implantable Collamer Lens (ICL) (STAAR Surgical, Nidau, Switzerland), the predominantly used posterior chamber pIOL, has experienced significant usage, with over 3 million ICLs implanted worldwide to date, compared to 1 million in 2019 and 2 million in 2022 (2, 3), underscoring its increasing acceptance and widespread use.

The ICL implantation is an effective procedure to treat myopia and myopia with astigmatism (4), but its complications can be more serious than keratorefractive surgery. Complications and long-term safety concerns include endothelial cell loss, cataract formation, secondary glaucoma (e.g., pupillary block and pigment dispersion), iris atrophy (e.g., pupil ovalization), traumatic dislocation, uveitis, and endophthalmitis (5, 6). A 10-year follow-up study on postoperative outcomes of ICL implantation reported an average endothelial cell loss of 5.3% at the 10-year mark and an anterior subcapsular cataract formation incidence of 10.5% during the 5 to 10-year follow-up period, with no vision-threatening complications noted throughout the follow-up (7). Additionally, a review on ICL implantation indicated that the incidence of intraocular pressure (IOP) complications ranged from 0 to 19.9%, the endothelial cell loss rate varied between 0.1–22.0%, and the rate of cataract formation ranging 0–3.85% (1, 8). However, the existing data on related complications show inconsistent results, with studies having single-center designs, small sample sizes, and potential selection bias. Moreover, intraoperative and postoperative complications are not only associated with inherent issues in ICL design but may also be influenced by improper ICL sizing and insufficient surgeon expertise. Nevertheless, comprehensive data on device-related issues and associated ICL complications remain limited.

The United States Food and Drug Administration’s (FDA) Manufacturer and User Facility Device Experience (MAUDE) database is a critical online repository that contains millions of medical device reports (MDRs) submitted annually by mandatory reporters, such as manufacturers, importers, and device user facilities. Additionally, a major advantage of the MAUDE database is its inclusion of reports from ophthalmologists with diverse backgrounds and practice settings, making the data more representative. Since its public availability in 1999, the MAUDE database has served as a vital resource for monitoring the performance of medical devices and identifying adverse events (AEs) associated with them (9). It provides real-world data that complements pre-market clinical trials, offering insights into device-related complications, malfunctions, and safety concerns that may not be evident during initial testing. This database has been widely utilized in research to investigate AEs associated with various medical technologies, including assistive technologies in ophthalmic surgeries (10), ophthalmic injectable drugs (11), and human implants (12–14). By analyzing reports of suspected device-associated deaths, serious injuries, and malfunctions, the MAUDE database helps patients, healthcare providers, and regulators make more informed decisions, ultimately enhancing patient safety and driving improvements in device design and clinical practice. Its role in facilitating post-market surveillance and supporting evidence-based medical decision-making underscores its importance as a cornerstone of medical device safety and regulatory oversight.

As the data is publicly accessible, de-identified, and does not involve new patient data collection, approval of the institutional review board (IRB) and ethical committee oversight were not required.

Our analysis of MAUDE data from 2015 to 2023 identified “shape and/or size issues” as the most frequently reported device-related problem, underscoring the importance of accurate ICL sizing in clinical outcomes. This finding aligns with prior literature suggesting that improper sizing is a key contributor to several complications. Oversized lenses may cause excessive vaulting, which can increase intraocular pressure through mechanisms such as angle-closure, pigment dispersion, or pupillary block (20). In contrast, undersized lenses can result in low vaults, lens rotation, and early cataract formation (21). Although current sizing strategies often rely on white-to-white measurements and anterior chamber depth, these approaches have inherent limitations (22). Our findings emphasize the need for continued refinement of sizing techniques to minimize vault-related complications and improve patient safety.

“Off-label use” is the second most common device issue, with a relatively low incidence in 2017 and 2018. However, it began to rise in 2019 and has since maintained a significant proportion. The trend in “Operation and control issues” exhibits an inverse correlation with “Off-label use,” showing elevated percentages in 2017 and 2018, followed by a significant decrease commencing in 2019, remaining below 3% in subsequent years. Given the introduction of the V5 model with a larger optical diameter in 2016 (23), it is plausible that users initially encountered a learning curve with new or updated products, resulting in a more cautious adherence to labeling guidelines. As experience increases, people may develop confidence in their methods. Nonetheless, it is crucial to emphasize that “Off-label use” represents a substantial portion of the top three complications in patients, ranging from 5.2–15% in both spherical ICL and toric ICL groups. This serves as an important reminder for practitioners to rigorously follow guidelines and labeling requirements to enhance safety and improve patient outcomes.

In the MAUDE database, reports of “No patient impact” accounted for the most patient-related AEs associated with ICL. The top three patient complications in both spherical ICL and toric ICL groups were “Vision issues,” “IOP issues,” and “Lens-related issues.” These findings align with previous studies indicating that complications after ICL implantation often involve increased IOP and corneal, lens, or retinal complications (24, 25). It is noteworthy that “Vision issues” was the most frequent patient-reported complication in MAUDE, despite earlier research suggesting comparable or better outcomes with ICL compared to corneal laser refractive surgery. This emphasizes the efficacy and reliability of ICL for refractive correction, which remains a significant issue. The FDA has provided specific standards to assess the effectiveness and predictability of outcomes following ICL implantation (26). Additionally, visual impairments may correlate with myopic regression and the formation of lens opacities over time, along with a deterioration in the optical characteristics of the lens post-ICL implantation (7).

Using Cramér’s V, we identified a moderate association between device issues and the three primary patient complications, suggesting that device-related factors may influence the incidence of patient complications. Notably, “Vision issues” were most closely associated with “Optical issues” in both groups. A 10-year retrospective follow-up study on ICL implantation for the correction of myopia and myopic astigmatism indicated that the safety and efficacy of toric ICL were comparable to those of non-toric ICL (7). Interestingly, in the toric ICL group, nearly 20% of “Vision issues” were associated with “Activation, positioning, or separation problems,” compared to only 2.1% in the spherical ICL group. The annual complication reports reveal that “Activation, positioning or separation problems” in the spherical ICL group decreased to below 1% post-2019, whereas incidents in the toric ICL group persisted between 6.9 and 12.7%. These results underscore the necessity for increased vigilance regarding positioning when utilizing toric lenses. IOP-related complications were primarily associated with “Shape and/or size issues.” As previously discussed, an oversized lens may result in a high vault, subsequently increasing IOP and leading to related complications (20).

Lens-related issues were strongly associated with “Shape and/or size issues.” Cataract formation in ICL patients may result from aging, lens trauma, or inadequate aqueous humor circulation (25). Aging is an unavoidable physiological change, and improper lens sizing can cause substantial contact between the ICL and natural lens, leading to cataract formation. The aquaport feature in newer ICL designs promotes aqueous flow, reducing the need for peripheral iridectomy and cataract risk (1). Surgeon experience, careful irrigation, and intraoperative technique also influence the lens opacity, as noted by Montes-Mico et al. (4). This may explain why “Operation and control issues” constitute over 10% of lens-related issues reports in both groups.

The statistical findings for the subsequent management of the three main complications indicate that the major treatment strategies are identical for both the spherical ICL and toric ICL groups. In cases of vision issues, approximately 50% involved lens exchange, which is also used to manage IOP issues. For lens-related issues, the main approach was lens extraction combined with secondary procedures. Following adequate follow-up management, the majority of issues associated with these three primary complications were addressed. João Heitor Marques et al. reported that the most common reasons for pIOL explantation are cataract formation and endothelial cell loss. After the timely removal of pIOL, both vision and endothelial cell density showed sustained improvement (27). A retrospective investigation on double lens extraction for eyes with pIOL corroborated this perspective while also indicating that some vision-threatening problems may occur post-extraction, including retinal detachment and diminished endothelial cell density, the latter being more prevalent (28). Additionally, the incidence of complications and the irreversible damage they may cause often necessitate further surgeries, which can impose economic burdens, psychological distress, and physical harm to patients.

This study has several limitations. Firstly, the lack of a known denominator prevented incidence rate estimation. Secondly, the use of MAUDE procedural term codes and electronic reports introduces inherent limitations, including underreporting—particularly those deemed minor or those effectively managed without further intervention, duplicate submissions, misclassification, and missing data. Importantly, the semantic ambiguity of reported terms—as well as variability in reporting sources (e.g., physicians, patients, or manufacturers)—may compromise data accuracy and consistency. In addition, some terminology was overly broad and lack the granularity needed for precise clinical interpretation. These semantic limitations, inherent to the MAUDE reporting system, may affect the clarity of our analysis and reduce its direct applicability in guiding clinical practice. Misclassification, in particular, could impact comparisons between different lens types. To mitigate this, we excluded cases with missing lens power or obvious duplication, and categorized data based on available lens power information. Furthermore, although we provide statistical summaries of adverse event reports, these data do not represent true incidence or prevalence rates. The MAUDE database lacks denominator information which limit its ability to yield population-level risk estimates. Therefore, caution should be exercised when interpreting the frequency of complications, and comparisons with findings from prospective clinical trials or registry-based studies should be avoided. Furthermore, although the MAUDE database enables large-scale analyses of device-related complications, it lacks global representation and may be affected by selection and reporting biases. These limitations underscore the importance of cautious interpretation. Nonetheless, we believe our findings are valuable in highlighting the real-world diversity of complications associated with ICL and in revealing longitudinal trends in adverse event reporting. Future research could benefit from multi-center collaboration and integration of international datasets to improve generalizability and data reliability.

Although several of the complications identified in our study—such as sizing problems, elevated intraocular pressure, and cataract formation—have been previously documented in clinical studies, the strength of our analysis lies in its use of a large-scale public adverse event database. This study should be interpreted not as a definitive clinical investigation, but rather as a real-world post-market surveillance summary. By analyzing trends and distributions of reported events from diverse sources, our findings contribute to ongoing safety monitoring and highlight key areas where further clinical research and regulatory attention are warranted.

This study offers a descriptive summary of post-market adverse events associated with ICL reported in the MAUDE database from 2015 to 2023. While the majority of cases indicated no patient impact, reported complications underscore the importance of appropriate lens sizing and adherence to clinical guidelines. This analysis provides valuable insights into safety signals and reporting trends that may inform future research and clinical vigilance.